Extractive lactic acid fermentation was investigated in the presence of sunflower oil and Alamine-336 (with oleyl alcohol as the diluent solvent). Lactic acid was produced in various media at 37 degreesC using Lactobacillus delbrueckii (NRRL-B 445). First, the effects of oleyl alcohol (33.3%, v/v), immobilisation, and immobilisation in the presence of sunflower oil (5, 10, 15%, v/v) on lactic acid production were investigated. It was found that oleyl alcohol did not affect production while addition of sunflower oil increased lactic acid production from 10.22 to 16.46 gdm(-3). On the other hand, a toxic effect was observed for oleyl alcohol solutions containing 15-50% (v/v) Alamine-336. A maximum total lactic acid concentration of 25.59 gdm(-3) was obtained when an oleyl alcohol solution containing 15% (v/v) Alamine together with immobilised cells with 15% (v/v) sunflower oil was used. This value was about 2.5 times that obtained from fermentation without organic solutions.